Gripping-in-liquid: Handling challenges for automated ultra-thin wafer production

New approaches for future photovoltaic cell concepts issue a challenge to crystalline wafer handling. Especially concepts based on ultra-thin silicon wafers force automation developers to look even beyond the aims of the international PV manufacturing roadmap. As widely known, crystalline photovoltaic wafers are a very sensitive object for industrial production, especially for gripper-based handling solutions. The known wafering method "SLliM-cut" requires an additional cleaning step after a single wafer was detached from the parent substrate. To clean organic residues off substrates an etching bath is applied. In general, the investigation takes a look on the potential threads for thin foils such as cleaning a particle contamination off the substrate's surface. The paper further discusses the opportunities and limits for the automated handling of ultra-thin objects in cleaning baths and presents an approach for a high-volume process control. The tested gripping principles and processing parameters for underwater gripping of ultra-thin wafers and the opportunities for withdrawing the ultra-thin wafers out of a liquid are presented.